CVE-2021-21424 : Exploit Details and Defense Strategies

This CVE record pertains to a vulnerability in Symfony, a PHP framework for web and console applications, that allowed user enumeration due to inconsistent handling when attempting to switch users. The impact of CVE-2021-21424, affected systems and versions, technical details, as well as mitigation and prevention strategies are detailed below.

Understanding CVE-2021-21424

This section provides insights into the nature of the vulnerability and its implications.

What is CVE-2021-21424?

The vulnerability in Symfony framework enabled user enumeration by distinguishing user existence through user-switching functionality, leading to a security risk.

The Impact of CVE-2021-21424

By exploiting this vulnerability, unauthorized actors could enumerate users without relevant permissions, potentially exposing sensitive information.

Technical Details of CVE-2021-21424

Explore the vulnerability specifics and affected elements.

Vulnerability Description

The issue in Symfony allowed unauthorized user enumeration due to inconsistent handling of user-switch functionality, posing a security threat.

Affected Systems and Versions

Symphony versions >= 2.8.0 and < 3.4.48, >= 4.0.0 and < 4.4.23, and >= 5.0.0 and < 5.2.8 are affected by this vulnerability.

Exploitation Mechanism

Exploiting this vulnerability involved manipulating the user-switch functionality to identify existing users, leading to a breach in user privacy.

Mitigation and Prevention

Learn how to address and prevent the CVE-2021-21424 vulnerability.

Immediate Steps to Take

Users are advised to apply the available patch for branch 3.4 to mitigate the vulnerability and prevent unauthorized user enumeration.

Long-Term Security Practices

To enhance Symfony security, users should regularly update to the latest versions, implement secure coding practices, and monitor security advisories.

Patching and Updates

Ensure timely installation of security patches and updates for the Symfony framework to address known vulnerabilities and bolster system security.